Fast, Quasi-Optimal, and Pipelined Instruction-Set Extensions

Now-a-days, many customized embedded processors offer the possibility of speeding up an application by implementing it using Application-specific Functional units (AFUs). However, the AFUs must satisfy certain constraints in terms of read and write ports between AFU and processor register file. Due to these restrictions the size and complexity of AFUs remain small. However, in recent some work has been done on relaxing the register file port constraints by serializing register file access (i.e., by allowing multi cycle read and write). This makes the problem of selecting best AFU significantly more complex.